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This story was printed from CdrInfo.com,
located at http://www.cdrinfo.com.
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1. Features

We have in our labs the Silencer Mk III 750W (PPC MK3S750) power supply unit from PC Power & Cooling, an OCZ Group company. The 750W version was added to the company's Silencer Mk III Power Supply Series at CES in January.

The power supply has been designed to meet the power demands of professional and enthusiast users, by providing a 750 wattage along with high efficiency and convenience and flexibility through a modular cable design.

The Silencer Mk III 750W meets the stringent 80 Plus Gold certification for energy-efficiency ratings and support over 90 percent efficiency under typical workloads. Featuring its popular Dual Thermal Control System (an operation that allows either PSU model to be switched between normal and silent modes), the Silencer Mk III works in conjunction with the load and temperature controlled fan for quiet operation. Additionally, the PSU combines a single +12V rail, premium components (including 100 percent Japanese 105°C capacitors), protection circuitries, continuous stable output at a 50°C ambient temperature, and heavy-duty chrome finish metallic cable connectors to provide excellent conductivity and lower resistance.

The Silencer Mk III 750W is backed by a 7 year warranty and retails for $140.

2. Opening the package

Below you see the white package if the PSU, which should look familiar to all those who may have read our review for the 1200W version of the same PSU, the Silencer MKIII 1200W.

The PSU's wattage, the 80PLUS Gold certification and the 7-year warranty of the unit to be prominently displayed on the front side of the box.

The back of the box lists the technical specifications of the PSU, its basic features along with an explanation of the Dual Thermal Control System. Using a slider switch found at the rear side of the PSU you can set the fan mode to Silent Mode or Normal Mode. Normal mode ensures that the fan is always running and thermally controlled. Silent mode forces the fan off until the unit reaches 50% load at which it then becomes thermally controlled:

The sides of the box also give the cable and connector configuration list:

Inside the box there is the PSU surrounded by foam, wrapped in a white cloth bag and sealed in plastic within.
Bundled with the Silencer is a manual, mains cable, screws and a set of cable ties.

The black bag you see above includes the modular cables. Each one has a metal connector instead of the plastic you typically see in PSU cables. It is said that is said to provide better and more stable electrical connectivity than regular plastic modular plugs:

Let's have a closer look to the main unit. The Silencer MKIII 750W PSU is painted white color. It's metallic case is mat and all of its corners are rounded for easier and handling.

On the top side there is a massive 140mm ‘B1402512H’ ball bearing, thermally controlled fan running on 0.36A and has a 2000rpm maximum speed. As we previously mentioned, there is a fan switch on the back of the PSU and this allows us to select two modes. In the first the fan is always on and temperature controlled. In mode 2 it is fanless up to 50% load and temperature controlled as required.

The interesting side of the PSU is the one with the 8 modular sockets. They are four 6-pin connectors for peripheral cables and four 4-pin for PCI-E cables. These are made out of metal and are actually 4-pin and 6-pin male connectors, with screw caps used to attach the wiring (the modular cables.) As we earlier saw, each module cable also features a female metallic connector.

All the male connectors on the PSU are protected by silicone cap, which should be of course removed when you plug in cable. It would be also decent not to keep any unused connectors uncapped, as this could cause a short. But even in that rare case, the PSU's Short Circuit Protection would kick in to instantly shut the PSU down and protect it.

All native cables are also fully sleeved back into the housing, and around the cable exit-hole is a grommet to protect cabling from sharp edges.

The back side is standard with the honeycomb venting as well as the AC input, the on/off and the Dual Thermal Control System switches:

3. Cables, PCB

The power supply utilizes a single 12V rail design to deliver most of the power for the unit. It can supply up to 62A at 12 V, almost its entire capacity (744 watts), at this voltage. The minor rails have 120W maximum combined output, which will cover all the needs of a modern system, and the 3A maximum that the 5VSB can output will suffice in most cases.

The maximum combined output of the PSU is 750 watts:

PC Power & Cooling Silencer MK III 750 Power

Rail

3.3V

5V

12V

5VSB

-12V

Max. Power

24A

24A

62A

3A

0.5A

120W

744W

15W

6W

Total Max. Power

750W

The Silencer Mk III provides plenty of cables and connectors:

Native Cables

ATX connector (625mm)

20+4 pin

4+4 pin EPS12V/ATX12V (640mm)

2

Modular Cables

6+2 pin PCIe (580mm)

4

SATA (400mm+150mm+150mm+150mm)

12

4 pin Molex (400mm+150mm+150mm+150mm)

4

FDD adapter (+100mm)

1

Below you see a picture of the internal of the PSU:

The components and their arrangement on the PCB contribute to an overall clean layout.

The MK3S750 is based on a half-bridge topology along with an LLC resonant converter for added efficiency. The secondary part of the main transformer includes a synchronous rectification circuit along with two VRMs for the generation of the minor rails.

As you see in the picture above, a pair of heatsinks run the length of the unit and separate the three main sections of the PSU: 1) the Active PFC (APFC) section (right side), which is actually a AC/DC converter controls the current supplied to the PSU so that the current waveform is proportional to the mains voltage waveform; 2) the transformer section (middle), which isolates primary from secondary side and converts (steps down) the voltage which feeds the secondary rectifiers that generate all DC outputs (+12V, 5V, 3.3V, 5VSB, -12V) and; 3) the output rectifiers and filters (left side) , which rectify and filter the high frequency switching waveform created by the MOSFETs and fed through the secondary of the main transformer.

In the APFC section, two Infineon fets chop the incoming rectified DC signal, a CREE C3D08060A boost diode and the PFC controller (NCP1653 IC). A hold up cap is provided by Nippon Chemi-Con having 560 μF capacity. The capacitor is rated at 105°C, 400V, KMQ series. There is also a thermistor responsible for protection against large currents and the relay that bypasses it once the start-up phase finishes.

On the secondary side, the +12V rail is generated using four IPP041N04N fets. All caps of the secondary side are provided by Nippon Chemi-Con and are rated at 105°C.

Where appropriate components are given extra stability by white adhesive and wiring it tied in place and plastic separators.

4. Measurements

For this test we monitored each of the rails of the PSU under various loads, which represent different power-hungry PC configurations. We took voltage measurements for 150W, 300W 450 W, 600W and finally 750W loads.

The current ATX specifications allow for the following fluctuations in voltage outputs:

3.3V Rail: 3.135V - 3.465V

5V Rail: 4.75V – 5.25V

12V Rail: 11.4V – 12.6V

An oscilloscope was also used to examining the voltage ripple on the rails using the proper capacitors in place to filter noise. This measures how clean the power delivery really is for the tested power supply. The ATX specifications' requirement for ripple is 120 mV for 12V and 50mV for the rest outputs.

In the crossload tests, we firstly stressed the two minor rails (5V and 3.3V) with a high load while the load at +12V was only 2A. For the second crossload test we applied the maximum load that the +12V rail could handle while the load on the minor rails was very low.

The results is illustrated below:

Voltage regulation

Efficiency

Noise

Ripple

LOAD

3.3V

5V

12V

3.3V

5V

12V

150W

3.33

5.12

12.16

90.45%

0 dBA

6.5mV

8.4mV

9.5mV

300W

3.27

5.06

12.12

92.34%

0 dBA

8.3mV

10.3mV

15.3mV

450W

3.21

5.00

12.01

91.75%

33.9 dBA

10.3mV

10.4mV

19.7mV

600W

3.18

4.97

11.97

91.36%

34.1 dBA

13.3mV

11.9mV

24.5mV

750W

3.17

4.93

11.91

90.30%

34.8 dBA

22.4mV

16.9mV

30mV

Result

OK

OK

OK

OK

OK

OK

OK

Crossload 1

3.27

5.05

12.13

85.06%

32.6 dBA

12.8mV

11mV

16.2mV

Crossload 2

3.23

5.11

12.02

91.06%

34.7 dBA

14.4mV

11.1mV

34.3mV

As you see below, the voltage deviations as well as ripple for all the outputs were well within the acceptable limits.

Voltage regulation at +12V is good, although we would expect a better behavior of the minor rails.

Efficiency was also high for all the loads and of course, higher than 80% in order to comply with the 80 Plus standard.

Regarding noise levels, we measured any audible sound from a 1m distance from the PSU. The fan was silent until the 300W loads. A low 34dB(a) was measured after the 450W point and reached the 34.8dB(A) under full load.

5. Final words

From a performance standpoint, the PC Power & Cooling SIlencer MK III 750W PSU is boasting a very good voltage regulation within its power spectrum along with very clean DC output. fan noise is low and the PSU's efficiency is high.

The device has been designed to power your SLI/CrossFire setups . Its massive single +12V (62A) rail has just so much power to handle multiple heavy duty graphics cards, considering that a graphics card uses 15A on average.

The PSU's $140 price is not as low as we would like, at least from the casual gamer's perspective. Considering that the Silencer MKIII 750W is facing the competition of other flagship products from Corsair and Seasonic - which are claimed to deliver top efficiencies and ripple suppression - it would be wise for OCZ to make this PSU more affordable.